Maxxis Hookworms

I read that the prefered tire for racing are the Maxxis Hookworms. So I bought a pair. Now I'm racking my head trying to figure out how to run these 3" wide beasts without chain rub. Or do the racers just let em rub because a race is short enough to not to wear through the tire?

My bad they are 2.5 " . I'll have to try shimming the motor cause that's whats screwing up the geometry . The frame is a GT2A with a pedestal front mount. I could cheat that over maybe an 1/8th or so. Not sure how to do the back mount though.

I stopped in because I thought the 'hookworm' tires were cool but maybe I can help.

The thing is, once you go wider than ~2.25" tires on a direct drive 2-stroke, the chain won't fit past the tire, and trying to modify your engine mount and rear sprocket is usually an expensive futile effort.

My basic build rule is if the tires at their widest point is over 2 ¼" you need pedal side drive.
Your bicycles pedal side always works.

That is just the price of going with a 2-stroke with fat tires, but to works well.
A SickBikeParts shift kit has worked well for me anyway.

Silly to do without bicycle rear wheel gears to take advantage of having geared engine power as a bonus, but doable, and you can always lace a new internal shifting hub into your back wheel.

These Kenda Flame tires are 2.65" and the chain clears.

You can go much wider, it just a matter of tying into the pedal drive.

I mounted my engine about a centimer offset from the center of the frame and the left pedal still clears the left side of the engine with about 3-4mm to spare. That will suffice for a 2.5 inch tire, but if you go over 3 inches it may not be enough and a jack shaft of sorts would have to be thought up for the left side moto-chain. If you are running a jack shaft for the right side so you get power to the bicycle chain and gears, then it's just a queation of tuning the dimensions in your jack shaft setup.

That is good advice. I don't really want to hassle with a jack shaft on this build mainly because I'm running mag wheels that can't switch hubs. I probably should have mentioned that right off the bat. Thank you though KCvale for the knowledge. Good to know if I make changes. And thanks Jaguar I will give that a shot.

when i first mounted my fat frank 2.35" it rubbed. I loosened all 3 mount points of the engine. my mounts are custom. after the engine was "loose" I jostled around and was able to get out of the rub. then slowly went around tightening the mounts little at a time while watching my chain path.

the head is maybe 2mm to the left of the frame, no bad vibration. been running probably over 300 miles so far. I am ordering new tires and they are 2", they don't come any wider so I will be running skinny again. well skinnier than I want, I like all the extra comfort I can get